Illuminated push-button system



Oct. 19, 1965 c. A. MELVIN ETAL 3,213,269

ILLUMINATED PUSH-BUTTON SYSTEM Filed Sept. 25, 1962 2 Sheets-Sheet l Wmmuss A. MELVIN l2 ROBERT GODBARSEN WILLIAM G. WAGGONER 4 I INVENTORS A TORNEY FIG. 2

Oct. 19, 1965 c. A. MELVIN ETAL 3,213,269

ILLUMINATED PUSH-BUTTON SYSTEM Filed Sept. 25, 1962 2 Sheets-Sheet 2 9, V v3s CHARLES A. MELVIN ROBERT GODBARSEN FIG 4 WILLIAM G.WAGGONER 4 d INVENTORS ATTORNEY United States Patent 3,213,269 ILLUMINATED PUSH-BUTTON @YSTEM Charles A. Melvin, New Berlin, Robert Gotiharsen,

Milwaukee, and William G. Waggoner, Eim Grove,

Wis, assignors to General Electric Company, a corporation of New York Filed Sept. 25, 1962, Ser. No. 226,07% 1 Claim. (Cl. 240-1) This invention relates to a push-button system in a control panel and particularly to such a system wherein actuated or push-in buttons are rendered strikingly visually distinguishable from non-actuated buttons.

In various types of control systems, it is necessary to select an operating value or magnitude for one or more parameters of interest. Thus, for example, in X-ray technology, for both medical and industrial radiographic applications, it is necessary to select, among other things, the time duration of X-ray exposure, the magnitude of the accelerating voltage for the electron beam in the X-ray tube, and the magnitude of the electron beam current. The magnitudes selected are dependent upon the nature of the test object in order to obtain the best radiograph. Each parameter may be continuously variable, but from a practical point of view is usually selected in magnitude from a few discrete values. When this is the case, push-button switches may be used to open and close electrical circuits to properly establish the magnitude of the appropriate parameter in the system. Thus, for the accelerating voltage of an X-ray tube, ten push-buttons may be disposed upon the control panel, representing voltage in kilovolt increments. Only one of the ten push-button switches can be actuated at one time, thereby establishing the accelerating voltage as that of the actuated push-button, the magnitude of which is typically inscribed upon the face of the pushbutton. In order for the operator to be fully and readily aware of the magnitude settings of the parameters for the current operation, it is desirable to illuminate the actuated button in a manner to insure that it is strikingly distinguished from the other, non-actuated buttons.

Furthermore, in X-ray technology, it is often the case that the control panel or console is disposed in a region removed from the X-ray equipment itself, and in an area of subdued light, so that unless all of the buttons are illuminated, it is difficult to see which button next to push for the next exposure. In such console arrangements, therefore, it is important that the legends on all of the push-buttons be readily visible, as well as distinguishable from those buttons which in fact have been actuated.

One solution to the problems posed by these requirements is to provide illumination of one color or light intensity level for all of the non-actuated push-buttons, and provide means for illuminating the depressed or actuated push-buttons in a different and preferably contrasting color or different level light intensity.

It is known in the art to provide this color or intensity differentiation between actuated and non-actuated pushbuttons in a panel. However, the systems known in the art usually require a multiplicity of different colored light sources, or where only two light sources are used, complicated electronic switching circuits are required.

It is the primary object of this invention to provide a push-button illumination system particularly adapted to X-ray application, wherein color intensity discrimination is provided to distinguish between actuated and nonactuated switches utilizing a single light source and no electronic switching circuitry.

The above object is accomplished in accordance with the principles of the invention by utilizing, for each pushbutton, a clear light transmitting material such as glass or acrylic plastic, the back portion of which is masked with an opaque surface, except for a transparent windowlike region surrounded by the opaque area. The pushbuttons are mounted on a panel behind which is located a source of illumination, preferably a white light, and a transparent colored or neutral density filter having a spatial relationship with the window of the push-button and the clear light. With the push-button in its nonactuated position, the white light has direct access to the window of the push-button, and the push-button is illuminated exclusively with white light. With the pushbutton in the actuated or pushed-in position, the filter is disposed between the white light and the window of the push-button in a manner such that light can enter the window of the push-button only after having first passed through the filter. Thus, in the actuated position, the push-button is illuminated through the window solely by the filtered light. In these circumstances, then, all of the push-buttons are illuminated by the white light except when actuated, at which time they are illuminated by colored light or light of different intensity.

A feature of the invention provides even illumination of the push-button, whether in its actuated or non-actuated position. The window in the opaque rear part of the push-button is disposed on a top or bottom surface of the button with the light and filter similarly disposed either above or below, to communicate appropriately with the window. The rear face of the push-button is inclined at an angle so that light coming down (or up) into the window is reflected off the angularly oriented rear face, and reflected forward to emerge from the front face of the push-button. It is important to establish the position of the rear face of the push-button relative to the position of the filter and the light source, in a Way such that the total area of the angled rear face is illuminated; this insures, in turn, that the total area of the front face of the push-button is illuminated, rather than just a portion thereof. Uniformity in the appearance of the emergent light is enhanced additionally by rendering the front end of the push-button translucent, rather than transparent, to thereby diffuse the emergent light.

In a preferred embodiment in accordance with the principles of the invention, two banks of push-buttons may be mounted relative to a single light source. In such an arrangement, the windows in the opaque surfaces of the bottom bank face upwardly, While those in the top bank face downwardly, and the source of illumination is located in between the two banks. A filter is provided adjacent to each bank of buttons between the light source and the bank.

The novel features believed to be characteristic of the invention are set forth with particularity in the appended claim. The invention itself, however, both as to its organization and method of operation, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings.

In the drawings:

FIG. 1 is a perspective cutaway view of an illuminated push-button system in accordance with the principles of the invention;

FIG. 2 is a front view of the push-button panel of FIG. 1;

FIG. 3 is a cross-section of the embodiment of FIG. 1 taken along line 33 in FIG. 2; and

FIG. 4 is a cross-section of the embodiment of FIG. 1 taken along lines 44 in FIG. 2.

In FIG. 1, a perspective view is presented of a bank of ten push-buttons mounted in a panel with coupling means for actuating switches; such an arrangement is particularly appropriate for use as an X-ray control panel. The bank comprises ten switches, numbered 1 through 10 in two rows, with the row consisting of switches 1 through 5 mounted above the row of switches 6 through 10. The front panel board 12 has two recesses to accommodate the two rows of push-buttons. The main function of panel 12 is to hide the working mechanism of the embodiment of FIG. 1, such that the viewer may see the front portions of push-buttons 1 through 11}, and nothing else. The front view of the control panel as shown in FIG. 2, demonstrates that the front panel 12 obscures all of the operating mechanism and permits the viewing of solely the front portions of push-buttons 1 through 10. Panel board 14, spaced a short distance behind panel 12, performs a function which has to do with optical masking and with structural support of the rest of the apparatus.

At the back face of push-buttons 1 through 10, there are thin, fiat rods 21 through 30, respectively. Each push-button is rigidly secured to its rod in a manner to be described below. The other end of each rod is connected to its own spring-loaded, push-type switch (not individually shown) all of which are housed in boxes 33 and 35 shown in FIGS. 3 and 4. The details of these switches are not the subject of the invention; many varieties well known in the art are available on an off-theshelf basis, and may be properly utilized in conjunction with the invention. In this particular embodiment, however, the switches in box 33 function interdependently with each other, but independently of the switches in box 35.

In each box, the switches are such that if any one of the five push-buttons in that row is pushed in, that switch is actuated and closes an appropriate electrical circuit. All of the other push-buttons either remain out, i.e., not pushed in or non-depressed, or if any one of the other four had previously been depressed, it springs back to an undepressed or unpushed-out position. Accordingly, of all of push-buttons 1 through 5, solely one of those pushbuttons may be pushed in at one time; similarly in the bottom row, only one of the push-buttons 6 through 16 may be pushed in at one time.

As may be seen more clearly in FIG. 1, button 5 has been actuated in the top row, and buttons 1 through remain in their non-actuated condition. In the bottom row, button 9 has been pushed in, while buttons 6 through 8 and remain non-actuated. Therefore, in box 33, the switch coupled to button 5 through actuating connecting rod 25 has been closed, thereby closing the electrical circuit coupled thereto. Similarly, the switch in box coupled to button a through its connecting actuating rod 29 is closed, completing its circuit.

Each of the boxes of switches 33 and 35 is secured to panel 14 in a rigid mounting arrangement comprising crossbars 37 and 37', and mounting bars 394s and 39'40' (see FIGS. 3 and 4). The support is identical for both the upper and lower assemblies. In the lower assembly the mounting bars 39 and 41) each have an end secured in panel 14 by virtue of screws 41 and 42. At the opposite ends of bars 39 and 40, crossbar 37 is rigidly secured to the ends of bars 39 and by screws not visible. As a consequence, panel 14 and bars 37, 39 and 40 form a rigid system, upon which other components are mounted.

Disposed within crossbar 37 at five separate locations are slots through which actuating rods 26 through 30 may freely pass in slideable relation therewith. Box 35, housing the switches to which actuating rods 26 through 30 are connected, is rigidly secured to crossbar 37 through mounting rods 45 and 46. Accordingly, with housing 35, crossbar 37, mounting rods 39 and 40 and the panel 14 forming a rigid construction, push-buttons 6 through 10 and actuating rods 26 through 311, as well as the switches internal to housing 35, may slideably and freely move between their non-actuated and pushed-in conditions.

A thin flat rod of a transparent green acrylic plastic 51 is secured parallel to and a short space behind panel 14. Its two ends are attached to mounting bars 39 and 40. The green acrylic rod 51 functions as an optical filter in a manner to be described below. Filter 51 is not only disposed behind panel 14, but a short distance above buttons 6 through 10. An identical green optical filter 52 is mounted across the bottom of mounting rods 39 and 4a ehind panel 14- a short distance below buttons 1 through 5. Consequently, both filters 51 and 52 provide a filtering function relative to buttons 1 through 5 and 6 through 18, respectively.

Secured to the back of panel 14 between filters 51 and 52 is a fluorescent lamp 55, preferably of a l3-watt rating, and having a length sufficiently great to extend from a point slightly to the left of button 1 to a point slightly to the right of button 5. Light source 55 is omni-directional and accordingly, light rays therefrom communicate freely with and through filters 51 and 52, as well as with the rear portions of buttons 1 through 10 through the space between filters 51 and 52 on the one hand, and panel 14 on the other.

Consider, now, the construction of one of the ten identically constructed push-buttons. The push-button 111, shown in perspective view of FIG. 1, is made of a colorless transparent acrylic plastic which may be machined or molded smooth on all surfaces to enhance its ability to transmit light. It is rigidly secured to actuating rod 3%; this may be simply done by casting the button upon the actuating rod. Button 10 is a right parallelepiped with a truncated rear portion such that the rear face is inclined at an angle to all the other of its faces. Accordingly, button 1% has top and bottom faces which are rectangles having different long dimensions, respectively; it has two side faces which are trapezoids; and two end faces, both of which are rectangular with the rear face inclined at an angle to the vertical. The front face of button 19 is covered by a thin sheet of light diffusing material upon which the numeral 10 may be imprinted or painted. The diffused front surface may be achieved by pasting on a thin, light diffusing material or knurling or otherwise frosting the face.

The rearmost portions of the bottom face, two side faces, a portion of the top face, and the entire rear face are opaque. If one were to pass an imaginary plane 61 through button 11) parallel to the front face, but at a distance of approximately more than half the length of the button along the top face from the front face, the bounds of the opaque regions would be established. All the surfaces to the rear of the imaginary line are coated with an opaque material, except for a small window 58 extending across the width of the top face and from the rearmost edge of the top face forward a distance less than the total distance between the rearmost edge of the top face and the imaginary plane 61. The opaque areas may be rendered opaque as shown by first covering those areas with a reflective coating such as a white paint and then with an opaque coating such as a black paint. In this Way, the inside faces of all the opaque areas readily reflect light, while the outside areas are poor transmitters.

The significance of this arrangement of opaque areas on the push-button may be understood when considering its geometry relative to filters 51, 52 and light source 55 as shown in FIG. 4. FIG. 4 is a view of the entire assembly taken as a cross-section through 4-4 in FIG. 2. Accordingly, the two push-buttons that are visible in that arrangement are button 4 on the top and button 9 on the bottom. Button 9 has been pushed in, while button 4 is not actuated. It may be seen that the clear window 62 of button 4 is located behind panel 14 facing downwardly towards lamp 55, and between filter 52 and panel 14. Accordingly, light rays from source 55 may pass directly into button 4 through its window 62; button 4 is thereby illuminated with white light. Indeed, the entire rear ffl Of utton 4 is so illuminated. Since the opaque surfaces are white and therefore reflective, the light from the rear face is reflected in many directions, but primarily outwardly to the left. Rays randomly reflected may not pass out from button 4 in the opaque regions. Accordingly, button 4, when viewed from the front of panel 12, is seen as illuminated with white light, and the numeral 4 stands out boldly on the face thereof.

Button 9, on the other hand, which has been pushed in, has its clear window 63 disposed upwardly toward source 55, but completely under green filter 51, such that no light from lamp 55 may enter window 63 of button 9, except after having passed through the filter. Accordingly, the only light that may enter button 9 is green. In manner similar to that of button 4, this green light is reflected to the left and passes out button 9. Accordingly, a viewer looking at the panel sees button 9 as green.

The geometry of the push-button need not be that of a parallelepiped. Other right, three-dimensional solids, such as a cylinder, wtih a truncated rear portion, may be used where environmental factors so indicate.

With the upper and lower rows of buttons having their clear windows 62 and 63 facing in opposite directions, a single light source 55 may provide illumination for both banks. The net result is the effect achieved by the representation of FIG. 2. In FIG. 2, buttons 5 and 9 have been pushed in, while all the others are out. All of buttons 1 through 4, 6 through 8 and 10 are white, that is, illuminated by white light through their respective windows, but buttons 5 and 9 are green.

It is of importance to arrange the window with the angle of the rear face of each button and the locations of the light source and the filters in a manner such that the entire rear face of each button is substantially completely illuminated solely by its required color light. Thus, if the angle of the rear face is incorrect, only a fraction of the total area of the rear face will be illuminated. Similarly, if the dimensions of the rear window and the spacing of the filters are inappropriate, some of the filtered light may enter the window when the button is not actuated and therefore tend to provide a color to the non-actuated button which should not be there.

The proper spatial relation of the various members is shown in FIG. 4. Thus, it may be seen that the extreme edges of the rear face 64 of unactuated button 4 are illuminated by light rays 65 and 66, respectively; these rays have not passed through the green filter. Therefore, the entire rear face is illuminated by white light. If source 55 were actually a point source, then no green light at all could enter window 62 of button 4. However, the slight amount of light that may enter after having passed through filter 52 is negligible. The actuated button 9 has its window 63 positioned completely under filter 51 so that light rays may enter only after having passed through the filter. Furthermore, it may be seen that the extreme edges of rear face 67 of button 9 are illuminated by green light rays 68 and 69, respectively. Accordingly, the entire rear face 67 is illuminated with green light.

The illustrative embodiment of FIGS. 14 may readily be modified to provide other color arrangements in accordance with the principles of the invention. Thus, a second set of filters different in color, e.g., red, from green filters 51 and 52 may be located in the same plane as those filters and disposed between those filters and panel 14. In such an arrangement the unactuated buttons would be illuminated with red light and the actuated buttons with green light. Removing filters 51 and 52 from such an arrangement and leaving the red filters contiguous to panel 14 results in the unactuated buttons being illuminated by red light and the actuated buttons by white light.

The colors of the filters and the light source are a matter of choice to be dictated mainly by the viewing conditions, commercial factors and visual psychological principles, as appropriate. Indeed, the filters need not be colored at all, but may be neutral density filters to provide light intensity rather than color differentiation among the pushbuttons.

While the principles of the invention have now been made clear in illustrative embodiments, there will be immediately obvious to those skilled in the art many modi fications in structure, arrangements, proportions, the elements, materials, and components, used in the practice of the invention, and otherwise, which are particularly adapted for specific environments and operating requirements, without departing from those principles. The appended claim is therefore intended to cover and embrace any such modifications, within the limits only of the true spirit and scope of the invention.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

An illuminated push-button system comprising: a panel, a plurality of push-buttons mounted on said panel and each comprising a material capable of transmitting light and having a plurality of surfaces, said surfaces including a right-parallelepiped form truncated at the rear end to define a rear rectangular face inclined at an angle to the front face and two parallel rectangular side faces having different dimensions in the direction between said front and rear faces, an opaque coating over said rear face and over that portion of the smaller of said two side faces continguous to said rear face and over a portion of the longer of said two side faces with the coating spaced a distance from said rear face to form a transparent region between said opaque coating on said longer face and said rear face, each push-button having an actuated and unactuated position relative to said panel, a light source mounted behind said panel and disposed to transmit light to all of said push-buttons, a portion of each of said push-buttons located behind said panel, optical filter means mounted behind said panel and interposed in a plane between said light source and said regions, said regions having such dimensions, respectively, and being disposed, when in one of said positions, to be in the propagation path of unconstrained light emanating from said source so as to be completely exposed to direct undeflected light from said source when in one of said positions and being disposed when in the other of said positions to be in the propagation path of unconstrained light from said source which first passes through said filter means so as to be lcogipletcly exposed only to direct undeflected filtered ig t.

References Cited by the Examiner UNITED STATES PATENTS 2,285,374 6/42 Doshmann et al.

2,440,063 4/48 Andrews 200l67 2,476,257 7/49 Hoff 240-1 X 2,693,165 11/54 Appleman 2402.l X 2,748,206 5/56 Andrews 200l6 X 2,831,453 4/58 Hardesty 2402.l X

NORTON ANSI-IER, Primary Examiner. 

